Effect of intraperitoneal nitroprusside and adrenergic agonists on food and water intake.
In previous works it was shown that catecholamine-induced hypodipsia is mediated by alpha1-adrenergic receptors while food intake (FI) inhibition supposes also beta-adrenergic participation. We used sodium nitroprusside (N) as a vasodilator, alone or mixed with various adrenergic agonists and measured FI and water intake (WI) in rats either deprived food and water overnight or in postprandial conditions after only 1 hour of deprivation in day time. N injected alone had no effect after overnight deprivation but diminished significantly norepinephrine (NE)-induced inhibition of both intakes, while epinephrine (E) inhibited only FI. In day time, N stimulated 30 min FI by 60% and WI by 84% in male but not in female rats. Isoproterenol (I) stimulated only WI (by 155%), while phenylephrine (P) and E inhibited it by 55%. In the presence of N, I increased WI even more (by 220%) but reduced FI. P + N and E + N increased FI by 41% and 128% as compared with P and E, respectively. Only P-induced inhibition of WI was canceled in presence of N. The results show that N, probably due to nitric oxide production, may induce hyperphagia and hyperdipsia in 1 hour-deprived male rats and also that catecholamine effects on FI and WI are differently modulated by N.
Racotta
R
R
Departamento de Fisiologia, Escuela Nacional De Ciencias Biologicas, Mexico, DF, Mexico.
Soto-Mora
L M
LM
Piñon-Lopez
M J
MJ
Quevedo
L
L
D000322:Adrenergic Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004326:Drinking / Q000187:drug effects*; D004435:Eating / Q000187:drug effects*; D004837:Epinephrine / Q000494:pharmacology; D005508:Food Deprivation / Q000502:physiology; D007274:Injections, Intraperitoneal; D008297:Male; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*; D014868:Water Deprivation / Q000502:physiology
D000322:Adrenergic Agonists; D014665:Vasodilator Agents; D009599:Nitroprusside; D009638:Norepinephrine; D004837:Epinephrine